is correct that baking soda will raise the ph kh and gh of water?
-if so how much do you dose

Baking Soda will raise the KH. It will raise pH to a maximum of about 8.5. Above pH 8.5, KH will continue to increase as you add more baking soda but pH will not.

I've always dosed it a little at a time and then re-measured the pH/KH. About 1 teaspoon per 10-15 gallons would be a fairly safe starting place.

Take care...

Tim

ok is calcium carbonate the same as baking soda or whaty some say to use bakeing soda others say to use clacium carbonate and irt rases the ghand kh

start with calcium carbonate to get the GH up to 4 or so. then measure KH and it will probably be close to 4 as well. if it is still lower than that you might want to add some baking soda. in any case start by practicing on a gallon of tap water to get a feel for the proportions needed. when adding to the tank go slow...

jtm

Baking soda is sodium bicarbonate.This will up the Ph.Calcium carbonate is similar and will also up the Ph .Carbonate hardness (Kh) will also go up.

oh yeah why do some poeple add baking soda to DIY CO2

My guess is to stabilize the Ph from going down during the reaction.Probably keeps the yeast active longer.